This invention relates to aerodynamic windows in general and is shown in combination with a gas laser. In lasers of low power, windows with physical walls made of materials which transmit the laser wavelength have been used, but subject window is for use when the laser beam will distort or disintegrate physical window materials. Other aerodynamic windows of this type are set forth in U.S. Pat. Nos. 3,604,789, 3,617,928, 3,654,569, 3,873,939 and application Ser. No. 437,114 now U.S. Pat. No. 3,907,409.